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[wahorger]

I encountered what I believe to be an issue with run-time error checking and formatted reads.

Reading a floating point using the 'A' format specifier should yield a run-time error, or an error that can be "trapped" at least.

The following code demonstrates this using both a floating point and a logical and reading with the "A" format specifier. The floating point read works (and gives a weird value, but the logical will throw a run-time error.

[mecej4]

I don't think that the Fortran standard is of much use in guiding us as to what should happen, given that the code is non-conforming. This is not one of the few errors that a compiler is required to issue an error message for.

Most compilers, unless asked to check errors, will assume that the programmer has taken care to match format items and I/O list items regarding type. Specifically, the problem is that the A in the format string does not match a character type item in the I/O list, but is used to read a REAL. Thus, whether an error message is to be issued, etc., depends on how much error checking is done.

Regarding the "weird" value of the REAL, here is the explanation. The data is read using the A format, resulting in placing the six characters into memory: '1', '2', '3', '4', '.', .5'. When you print the contents of abcd as a real, only four bytes are used, i.e., '1', '2.', '3', '4'. The hexadecimal representation of the real is thus Z'34333231'. Taking this as an IEEE-32 real gives us the value 1.6688934E-07, which is probably the "weird" value that you mentioned.

You can see this yourself by using the output statement

[PaulLaidler]

I have tested this code under Win32 and x64 and in both cases I get a runtime exception "Format/data mismatch". I don't think this feature has been added since the last full release but maybe it has.

P.S. Sorry I miss-read the post. I will note the omission.

[John-Silver]